Method for manufacture of compound agglomerate containing fuel



R. G. M'dOPHERSON 2,136,591

Filed March 9, 1956 2 Sheets-Sheet 1 Nov. 15, 1938.

METHOD FOR MANUFACTURE OF COMPOUND AGGLOMERATE CONTAINING FUELInveaafor: a. Maol'oaehsom Noir. 15, 1938. R. G. MWPHERSON METHOD FORMANUFACTURE OF COMPOUNDAGGLOMERATE CONTAINI [NG FUEL Filed March 9, 19562 Sheets-Sheet 2 .13708325173: Boy $.Maolizezagon; y r

PatentedNov. 15, 1938 UNITED STATES METHOD For: mmacruns or conrompAGGLOMERATE coxrammo Roy G. Macl'her'son, Framinghan Mus. ApplicationMarch 9, 1936, Serial No. 67,774 4' Claims. (01. 44-10) This inventionrelates generally to the art of fuel production, and more specificallyto a novel and improved process and apparatus for making at low cokingtemperature an anthracitic com- 5 pounded fuel, primarily for domesticuse, or the making of gas. The process is useful also for makingagglomerates for use in metallurgical and other fields.

The domestic users of coal require preferably a free but steady burningfuel, that is free from dust and gives off but little 'smoke. Withoutquestion, properly prepared anthracite coal is the nearest approach nowavailable to an ideal fuel for that purpose, but the commercial supplyof sizes larger than silt or fines is relatively limited, and expensive.

Soft coal,of which there is an unlimited supply of varying qualities, atreasonable prices, is well adapted for steam making and kindred purposeson a large scale, but not for household use, be-

cause it lacks the qualities already recited as desirable for thatpurpose. of fine sizes of both kindsof coal there is an immense'quantitythat cannot be used satisfactorily for domestic purposes.

Many attempts have been made to make an agglomerate or compound coal,so-called, of anthracite and bituminous fines, or slack, both separatelyand together, and with and without other materials, compressed with abonding material of some kind, and in the form of briquettes, or Jovoids. Such coals or fuel have some merits, but the art has never beencommercially very successful. Coke made from soft coal of various kindshas long been used, but such coke usually has been the by-product ofprocesses for distilling gases of various kinds, at high temperature,and the coke has therefore been porous, quite low in volatilecontent,and not entirely satisfactory for '40 domestic use, as might beexpected. Coke for domestic use should be dense in structure, and freeburning.

. While most bituminous coals will make a dense coke, if heated slowly,it has been found prac- 45 tically impossible to convert any naturalbituminous coal alone into a dense, low temperature coke-like fuelimmediately and rapidly. But I have discovered that a properly preparedmixture of bituminous coal and other materials or ele- 50 ments can bequickly and satisfactorily treated by my novel method, and therebyproduce a novel fuel. So far as I have been able to ascertain, allcommercialsoft coals are too rich in volatile content to be handleddirectly. They need to be '55 diluted with less volatile solid material,

The diluting agent may be a burnable material, as anthracite fines, orcoke breeze,'or semi-coke made for the purpose. or it may even beincombustible material, such as lime,.ores, or even common sand. 6

While much time and effort have been expended in the attempt to make asatisfactory product for domestic use, from soft coal, I am convincedthat one or more elements besides the soft coal are needed forsatisfactory production. 10

The best material to be used in any given case will be determine by theparticular use for which the product is to made, and the availability ofthe supply of these materials.

A mixture of soft coal and anthracite fines, or 5 crushed lumpanthracite, with a suitable binder,

treated primarily for fuel'andnot for distillation of other products,makes a very satisfactory, free a and long burning material for domesticuse.

Many materials may be used as binders, and 20 their'character may affectmaterially the resulting product. Bunker oil, starch solutions, evenwater, have been used. A thin tar, obtained as by low temperaturecoking, is a. satisfactory binder. I

A heavy coal tar usually 'facilitates the blending power of a compound,and decreases the amount of bituminous coal to be used.

Molding of the mixture in some form is desir-' able in the making ofdomestic fuel, as it increases 30 the compactness of the originalmixture, and renders it more convenient for subsequent treatment.Accordingly, the present invention is directed to the production of animproved, novel compound fuel, by a novel process and apparatus. 35

In the drawings of one embodiment of my novel apparatus for carrying outmy improved process described and illustrated herein:

Fig. 1 is a longitudinal section, with parts in elevation, of oneembodiment thereof 40 Fig. 2, a vertical cross section on line 2-2 of 1,looking toward the right; and Figs. 3 and 4, modified forms,respectively, of

the apparatus shown in Fig. 1.

I first mix my materials in any suitable manner, the proportions of thevarious ingredients depending upon the character of thevariousindividual materials used and. the type of product desired. Anthracitefines is inexpensive and readily obtainable, and yard screenings arevery satisfactory for use with bituminous coal. I prefer that the dryingredients shall be ground or classified to pass a l0 mesh screen.

When anthracite silt is used with the soft coal, the liner theanthracite silt the greater the pers5 centage of soft coal that must beused within practical limits. For example, I have found that 30 parts ofsoft coal and '70 parts of yard screenings, as usually-obtained locally,with 8 parts of light tar, all by volume, made a satisfactorycombination. These proportions, however, will vary accord ng to thedegree of fineness of the materials and the kind of tar used. 1

After mixing the material A, Fig. 1, it is preferably fed to anendless-conveyor l, travelling on a driving roll 2 and pressure roll I,and driven from any suitable means, not shown. I have discovered thatthere is a distinct advantage in treating my product in the form of aribbo or elongated sheet. The cost of manufacture is relatively low, andthe process may be substantially continuous. l

Immediately above and cooperating with the roll I is a second pressureroll l, mounted adjustably to vary the amount of pressure as desired,and controlling the thickness of the ribbon of material passing throughthe rolls.

. The conveyor delivers the mixture upon a table 5, suitably secured, asby securing its flanged ends 6 to the end walls of a retort, or closedchamber I, with a non-oxidizing atmosphere around the material, and ofkettle iron, chrome iron, or other suitable material, and of properlength,s'ay20to30feet.

The retort is properly housed in a prick or other setting l, with afront wall 0, fire arch II, baiiies II, as needed. and rear wall i2,forming a combustion chamber with a flue-|2a leading to' a chimney, notshown. The retort housing is provided with ports ii for supplying fuelgas, also a nozzle II for gas,.if desired, and again may have an oilburner II of convenient type and size, or the combustion chamber may beheated in any of the ways of engineering practice. 7

This retort has, at its rear end, a downwardly inclined chute II, ordischarge passage, leading to a combined storage and curing hopper ll,or

other receptacle, suitably supported, with one or more outlets I! fordrawing of! any gaseous products or vapor, and "at the hopper's lowerend, it

- has a discharge outlet 2!, provided with any suitable valve forsubstantially excluding the air from the hopper l8. This valve may be acone-shaped element 2|, operated by a rod extended through the hoppertop, and pivoted on a post 24, and provided with a weight or other meansfor causing the valve to remain normally closed.

The hopper I. may discharge into a second similar hopper 25, also closedby a suitable valve 26, conveniently controlled, as by a lever 21, thepurpose being ordinarily not to have more than one of these valves 2| or28 open at the same time.

It has been proposed, among other methods, to extrude a coal compound ormixture under pressure through a tube subjected to substantially acoking temperature, so that the extruded compound would be coked whendischarged. This plan, however, has many disadvantages and diillculties.It has been found by experience diflicult to cause the molded compoundto flow and ex-' trude continuously without frequent interruption, thuscausing shut-downs'of the machine.

Briquettes have been made and carbonized, but this process is expensiveand diflicult; it requires means to produce tremendous pressure, and itis diflicult to maintain an airtight seal to the retort while feedingthe briquettes to it, and it is exceedingly hard to apply a propertemperature to the briquettes, as they disintegrate with applicaon ofhigh heat, and again because, atcoking temperatures they will fusetogether, unless well separated. Unless they can be so treated, theymake an inferior fuel, as compared to my novel product, astheywill'dislntegrate on the fire before they are consumed, and burnwith a smoky flame. I have discovered that by compressing the materialinto a wide ribbon, or into an essentially continuous sheet of desiredwidth, bonded to hold its shape until the exterior surface sears overfsufllciently to ensure its final form, and then treating it atso-called low temperature of approximately 1400 to 1600 F.. it ischeaper, and far more satisfactory as a compound fuel than any that Iknow of.

The material, Fig. 1, atter passing between the compressing rolls ontothe plate 5, is deposited upon a suitable endless conveyor 28, as awoven wire belt on rollers t l, suitably driven as by an exterior drivebelt II, from and by driving elements not shown. The belt 2! may traveloveridlers 32, if desirable for support.

As the material is fed to the plate 5, after being compressed to asuitable thickness, say one to two inches, a hinged, or spring, cover 33presses lightly thereon, to help keep it from buckling, if so inclined,and to practically prevent the ingress of air to the retort, and thematerial then passes through the retort I, which is properly heated,

sayto about 1400 I. As the sheet of material approaches the forward endof the retort, a star wheel 34, driven by any means, not shown, or anyother convenient device, may mark and crease the sheet regularly to anextent suillcient to help cause the sheet to break into pieces of fairly1miform size, as they drop into thehopper It, or in subsequent handling.h

By closing the valve 28, and discharging the fuel into the hopper 25through valve 2|, only a minimum amount of air will be admitted to thehopper l8 and retort By closing the valve.2|

and opening the valve. 26,'the iuel may be discharged from the hopper 25into a car or other receptacle, without admitting morethan a smallquantity of air through the valve 2|.

The cycle of operation of valves- 2| and 26 may -be regulated to suitthe manufacturing conditions. v

- With temperature of approximately 1400 F., the mixture should yieldits volatile products to the desired extent, and in effect cokesatisfactorily in about 13 to 15 minutes in the retort.

By the foregoing process, the bituminous coal .will part with some ofits volatile content, and

combine with the anthracite fines to form a dense mass, and I cancontinuously, and at low cost, produce a dense anthracite agglomerate orcompounded fuel of convenient sizedpieces, free and long burning, havinga heating value essentially equivalent to that of the bestgrades ofanthracite, and burning with no hard clinkers. The ash content may beregulated by the selection of suitable raw materials.

It is further to be understood that the actual arrangement of theelements of the apparatus used may be varied. For example, Fig. 3, thepressure rolls 3, 4, may be located within the retort, and kept cool, i1desired, through the means of hollow shafts 35, carrying water or steamtherethrough.

Another variation which may be used is shown in Fig. 4. wherein thematerial is compressed and formed into a sheet by means of a suitablepress 36, operated by either toggles, cylinder and piston means 21, orotherwise, and resulting in an intermittent, yet substantiallycontinuous feeding motion of the ribbon of material.

Reasonable variation in the length of time required for the material totravel through the retort may be accomplished by adjustment of speed ofthe conveyor, or by allowing the material upon discharge into the hopperI8 to remain therein and mull inits own heat for the desired time. Smallquantities of air may be admitted here, or into the hopper 25, tosupport a partial combustion, and thus furnish additional heat fortreatment, if desired.

My invention is not restricted to the particular form or embodiment ofmeans for practising it herein shown.

I claim:

1. The process of making compounded smokeless fuel comprising mixingabout ten to thirty parts of comminuted coking coal with about ninety toseventy parts of comminuted non-coking coal and enough volatile liquidlubricating medium to serve as a temporary binder without substantiallychanging its character as a dry mixture, compressing the mixtureessentially cold to form a self-sustaining continuous strip ofapproximately the density of an anthracite coal product, freelysupporting the compacted strip while passing it through a heating zonecontaining substantially no oxygen in the surrounding atmosphere at acoking temperature for a period sufficient to volatilize and coke thebinder and part of the coal thereby causing the coking and non-cokingcoal to agglomerate in a hard dense coke-like mass having a specificgravity approximating that ofthe non-coking coal used, said masscontaining suflicient volatile matter to be free burning in domesticheaters, and separating said mass into convenient size pieces fortransportation and use. I v

2. A continuous process of agglomerating coking and non-cokingcomminuted solid material comprising mixing a smaller proportion ofcoking material and a larger proportion of non-cok ing material withsuflicient volatile liquid to serve as a temporary binder whencompacted, rolling the mixture without preheating to compress it into aself-sustaining continuous strip with a density of the order of theaverage of non-cokable constituents in the raw state, freely supportingthe strip thus formed while conveying it through a non-oxidizing heatingzone at a coking temperature for a suflicient time to volatilize thebinder and sinter together the coking and noncoking material in a harddense mass, and separating said mass into fragments of desired size.

3.'A continuous process of agglomerating coking and non-cokingcomminuted solid material comprising mixing a smallerproportion ofcoking material and a larger proportion of non-coking material withsufiicient volatile liquid to serve as a temporary binder whencompacted, pressing and scoring the mixture without preheating tocompress the same into a self-sustaining con tinuous strip with adensity of the order of the average of non-cokable constituents in theraw state and containing depressions at regular intervals, freelysupporting the strip thus formed while conveying it through anon-oxidizing heating- Zone at a coking temperature for a sufficienttime to volatilize the binder and coking and non-coking material in ahard dense mass, and separating said mass into fragments along lines offracture corresponding to said depressions.

4. A process of making a dense solid agglomerate containing carbonuniformly distributed throughout the mass, comprising mixing coking coalin lesser amount and non-coking sol d material in greater amount with a,suflicient amount of liquid binder to hold the mixture together withoutchanging its dry character when compacted, continuously feeding andcompacting the mixture without preheating, and controlling the degree ofcompacting to ritain a density of product of the order of the average ofthe non-cokable constituents in the raw state, exposing the compactedmaterial for a substantial length of time before coking it, conveyingsaid material through an oxygen free atmosphere in a coking zone at acontrolled rate of speed and while free from restraint subjecting it toa temperature sufficient to cause the volatilization and coking of" thebinder and coking coal to form a dense solid agglomerate containingsolid carbonaceous material and a sinter together the v minimum amountof volatile material suitable for charging to 'a furnace.

RO Y G. MAcPI-IERSON.

